Choose Werd if it's CHF 200 cheaper per month, the commute to HB is 6 min shorter — more central and connected, there's a denser restaurant scene.
Choose Wollishofen if it's noticeably quieter (48 vs 58 dB), it scores higher on safety (8.5 vs 6.5/10), it has better green-space access (7.5 vs 3.5/10).